[Patch V2 13/13] genirq/msi: Provide helpers to return Linux IRQ/dev_msi hw IRQ number

[Megha Dey <megha.dey@intel.com>]

From: Dave Jiang <dave.jiang@intel.com>

Add new helpers to get the Linux IRQ number and device specific index
for given device-relative vector so that the drivers don't need to
allocate their own arrays to keep track of the vectors and hwirq for
the multi vector device MSI case.

Reviewed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Megha Dey <megha.dey@intel.com>
---
 include/linux/msi.h |  2 ++
 kernel/irq/msi.c    | 44 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/include/linux/msi.h b/include/linux/msi.h
index 24abec0..d60a6ba 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -451,6 +451,8 @@ struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode,
 int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec,
 				   irq_write_msi_msg_t write_msi_msg);
 void platform_msi_domain_free_irqs(struct device *dev);
+int msi_irq_vector(struct device *dev, unsigned int nr);
+int dev_msi_hwirq(struct device *dev, unsigned int nr);
 
 /* When an MSI domain is used as an intermediate domain */
 int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c
index 047b59d..f2a8f55 100644
--- a/kernel/irq/msi.c
+++ b/kernel/irq/msi.c
@@ -581,4 +581,48 @@ struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
 	return (struct msi_domain_info *)domain->host_data;
 }
 
+/**
+ * msi_irq_vector - Get the Linux IRQ number of a device vector
+ * @dev: device to operate on
+ * @nr: device-relative interrupt vector index (0-based).
+ *
+ * Returns the Linux IRQ number of a device vector.
+ */
+int msi_irq_vector(struct device *dev, unsigned int nr)
+{
+	struct msi_desc *entry;
+	int i = 0;
+
+	for_each_msi_entry(entry, dev) {
+		if (i == nr)
+			return entry->irq;
+		i++;
+	}
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(msi_irq_vector);
+
+/**
+ * dev_msi_hwirq - Get the device MSI hw IRQ number of a device vector
+ * @dev: device to operate on
+ * @nr: device-relative interrupt vector index (0-based).
+ *
+ * Return the dev_msi hw IRQ number of a device vector.
+ */
+int dev_msi_hwirq(struct device *dev, unsigned int nr)
+{
+	struct msi_desc *entry;
+	int i = 0;
+
+	for_each_msi_entry(entry, dev) {
+		if (i == nr)
+			return entry->device_msi.hwirq;
+		i++;
+	}
+	WARN_ON_ONCE(1);
+	return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(dev_msi_hwirq);
+
 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */
-- 
2.7.4